The invention relates to a device for controlling the power supply of an electric starter motor of a motor vehicle, and of an automobile in particular.
Traditionally, the power supply for an electric starter motor is controlled by an electromechanical power contact (coil relay) which is actuated as a function of the status of the vehicle circuit breaker, either directly or by way of an electronic management device, integrated or not integrated in the starter.
In any event, the power contacts of automobile starters may be the cause of excessive voltage drop at the terminals of the electric starter motor. There may be various reasons for such a voltage drop, including contact corrosion, oxidation caused by arcing, short-circuit caused by deposits of copper dust engendered by the arcing, chatter when the contact closes, premature closing of the contacts even before the pinion has engaged sufficiently in the starter crown wheel, etc.
One of the objects of the invention is to address these problems.
According to a first aspect of the present invention there is provided a device for controlling the power supply of the electric starter motor of the vehicle, and of an automobile in particular, comprising a power switch connected in series with said electric motor to control the power supply to said motor, wherein the power switch comprises a controllable electronic power component.
Advantageous features include the following, considered alone or according to all their technically possible combinations:
The electronic component is a power transistor;
The electronic component is controlled by a management unit;
The movement of the starter pinion is controlled by an electro-magnet, the coil of which is connected in series with a second electronic component the power of which can be controlled, which is itself controlled by the management unit and which controls the power supply of said coil.
The second electronic power component is a power transistor.
The second power component is controlled by a cyclic pulse-width-modulated signal.
The management unit receives the voltage at the input at the terminals of the coil, and comprises means to detect the stabilisation of this voltage, as well as means for modifying the cyclic ratio of said pulse-width-modulated signal when this stabilisation is detected.
The management unit comprises means to control the transition to the passing state of the power component, which controls the power feed to the electric motor when this voltage stabilisation is detected.
The power transistors may be of the MOSFET type.
According to a second aspect of the invention there is provided a starter unit for a motor vehicle, and for an automobile in particular, comprising an electric motor, a pinion intended to be started by said motor, media to move said pinion from a position of rest to a position in which it engages with a crown wheel of the internal combustion engine, and a device to control the power supply of its electric motor, wherein the device is in accordance with the first aspect.